Photodynamic therapy of malignant tumors--recent developments.

Photodynamic therapy (PDT) is a promising new cancer treatment modality in which tumor cells are killed as a result of photoactivation of a tumor-localizing photosensitizing agent. Since activating light can be targeted specifically to tumors, and tumor-selective photosensitizing agents are being developed, this treatment has the potential to induce highly selective destruction of malignant cells. To date, PDT has been applied to a large variety of human carcinomas, resulting in successful eradication of single tumor nodules and several types of superficial tumors. Current research is aimed at improving the efficacy and tumor-selectivity and tumor destruction. The most immediate benefits of PDT are likely to be seen in patients treated with a combination of this and other forms of therapy.